In recent years, a CAE (Computer Aided Engineering) system is extensively used for a product development process to reduce development costs or shorten a design development period. The CAE system (hereafter referred to simply as CAE) creates an analytical model using shape data generated with a CAD (Computer Aided Design) system. The CAE performs analyses such a strength analysis, a fluid analysis, and a vibration analysis by using an analysis technique such as a finite element method or a boundary element method, based on the analytical model.
With respect to analytical model creation in the CAE, there is a known technique that uses an existing analytical model to create a desired analytical model. An example is disclosed in JP-A No. 2003-108609 as “morphing method for structural shape”. The “morphing method for structural shape” in JP-A No. 2003-108609 provides multiple reference points for an existing analytical model. The method moves the reference points on the basis of a correspondence relation between the reference points and a mesh model contained in the existing analytical model, and deforms the mesh model of the existing analytical model as moving the reference point, thereby making it possible to create a desired analytical model. The technique using an existing analytical model can eliminate the need for settings such as mesh data creation and a boundary condition and greatly reduce the load of the analytical model creation.
A method referred to an interaction analysis is known in an analysis using an analytical model with the CAE. An example thereof is disclosed in JP-A No. 2000-352545 as “fluid-structure interaction analysis apparatus”. When performing an interaction analysis by interacting a fluid analysis and a structural analysis with the “fluid-structure interaction analysis apparatus” of JP-A No. 2000-352545, first obtaining a deformation volume of an object by using the structural analysis, after that, moving nodes corresponding to an analytical model in a space for the fluid analysis by the deformation volume of the object associated with the structural analysis, and obtaining a deformation for each node on the object. In this manner, the apparatus can realize an interaction analysis between the fluid analysis and the structural analysis while interlocking analytical model shapes of the space and the object. Such interaction analysis can provide a fluid analysis in consideration of object deformation.
As mentioned above, the CAE needs to create an analytical model. The analytical model creation requires a large quantity of work, which includes generating mesh data from shape data such as CAD data and then supplying parameters and a boundary condition to each mesh in the mesh data. Accordingly, the CAE is expected to reduce as much workload as possible in the analytical model creation.
In many cases of product development processes using the CAE, an object to be newly analyzed can be obtained by merely adding a partial shape change as miner change to an existing object which has been already analyzed. Therefore, when creating an analytical model of such an object with the partial shape change, the analytical model can be created by merely adding the partial shape change to an existing analytical model which has been already analyzed. For this reason, according to the above-mentioned method (existing analytical model-reusing method) of creating a new analytical model (target analytical model) by reusing the existing analytical model, it is possible to effectively reduce a workload in the analytical model creation. However, when applying the existing analytical model-reusing method to a combined analytical model, there is room for improvement.
Here, the combined analytical model means an analytical means in which multiple partial analytical models are combined into one analytical model and a mesh for each partial analytical model has no continuity in a boundary between adjacent partial analytical models. When the existing analytical model-reusing method is applied to the combined analytical model, it is need to add a shape change individually to each partial analytical model in an existing combined analytical model. Even if the existing analytical model-reusing method can be applied to the combined analytical model, the combined analytical model increases a workload on creating an analytical model and needs to be improved.
The concept of the interaction analysis in JP-A No. 2000-352545 is effective for improving the workload problem in the combined analytical model. When the existing analytical model-reusing method is applied to the combined analytical model, it is often sufficient to make a shape change to one of partial analytical models constituting the combined analytical model. When the concept of the interaction analysis can be applied to such a combined analytical model, a shape change may be made to one of partial analytical models in the existing combined analytical model and may be also reflected on the other partial analytical models. This makes it possible to greatly decrease a workload on creating an analytical model also for the combined analytical model.
The technique in JP-A No. 2000-352545 allows a deformation result obtained by the structural analysis to be reflected on an analytical model in the space for the fluid analysis. The technique is inapplicable to a shape change for examining an optimum product shape during a design process. When the product design process causes a minute shape change, for example, the technique in JP-A No. 2000-352545 can interlock the changed shape between partial analytical models. When a large shape change is made to one partial analytical model such as changing a projection 10 mm long to 50 mm, however, simply moving nodes distorts a mesh and degrades the analysis accuracy. When a design change is made to add or remove a rib or a hole, only moving nodes cannot interlock shapes between partial analytical models. In such case, deforming one partial analytical model needs to be followed by deforming an adjacent partial analytical model.
The present invention has been made in consideration of the foregoing. An object of the present invention is to create a desired analytical model in a laborsaving manner when an existing analytical model is reused to create the targeted combined analytical model.